The invention relates to a clamping device for temporary suspending a drill or casing string from a drill floor, in which a wedge device forms a substantially circular releasable attachment in an opening in the drill floor and is provided with a series of clamping dies having an engagement surface with variable curvature for engagement with the cylindrical tubular, and a spherical seat for support of the clamping device in the drill floor.
In drilling operations, e.g. exploration and production drilling for oil and gas, clamping devices are used in many situations to engage a cylindrical body, for example a pipe, in particular to suspend a drill pipe within circumscribing structures. One example of this is slips or slips means within a rotary table on a drill floor.
Since tubulars with different pipe diameters are used, a technique is used today where clamping dies, slips and other components that engage with the external pipe surface to retain the tubular in a firm grip, need to be replaced when changes in the external pipe diameter occurs. This is time consuming and costly, and it implies that several sets of clamping devices need to be available at a location that often suffers from lack of space.
When the drilling operations take place from a floating installation, e.g. a floating drill rig or a drill ship, the installation will be moved due to waves and currents in the body of water, and these motions can by a rigid connection between the clamping device and the drill floor result in that the drill string is subjected to bending loads from the clamping device.
The object of the invention is to assist or reduce at least one of the disadvantages of the prior art technology.
The object is achieved by the features that are presented in the description to follow and in the appended claims.